Then the simplest approach for you is the Rubinstein Variation 1.d4 f5 2.c4 Nf6 3.Nc3. IM Cummings has a nice chapter on this in his book on the English, though I reject one of his recommendations. Overview:

You may not like systematically study an opening, but playing through several high level games (don't neglect golden oldies) will help you well on your way.The plussides are obvious:

1) no French, just 1.d4 e6 2.c4 f5 3.Nc3.2) you may consider 1.d4 d6 2.c4 f5 too (2...e5 is the spanner in your wheel) and certainly will enjoy 1.d4 g6 2.c4 f5 3.Nc3 and 4.h4.3) you fight the game on your own battleground.4) this classical approach is hardly worse than the main lines with 2.g3 and not worse than entering the French labyrinth either.5) but it's a lot less work, because White makes an important choice at his/her 4th move.

Someone should write a book about meeting the Dutch with 1.d4, 2.c4 and 3.Nc3.

The book had the effect good books usually have: it made the stupids more stupid, the intelligent more intelligent and the other thousands of readers remained unchanged.GC Lichtenberg

Entering the Dutch via this move order is all right for both sides, I think. Personally I want a starting point for entering mainlines, not more. So this repertoire is all right, sufficient for my level. And it integrates the Nimzo 4.Qc2.

My situation is somewhat funny. As child I played through Mieses/Dufresne - Lehrbuch des Schachspiels from my father's bookshelf, 1939 edition. So basically I learned the names of the openings and the first four to five moves from a time, when many 1.d4 Nf6 variations were still called irregular. Then playing 1.e4 and 1.e4 e5 and a Tarrasch defense of the queen gambit like system lead me to nearly 1900 with a 2050 peak after some serious tactic training. Then I paused tournament chess for 25 years and came back the last 10 years.

I played some correspondence games trying 1.b4 in the times without tournaments. This taught me, in spite of good results, to seach the center of the game around d4, d5, e4, e5 and not around b4, b5.

Chess knowledge really has developed. But I distrust 1.f4. From is solid, positional systems too, so black has a good choice according to his tastes(!). 1.b3 maybe all right if I knew more about different resulting structures.

This is a little off-topic in a French forum. A consequence of an error of my side.

Medical textbooks say I should be dead since April 2002.Dum spiro spero.

About two years ago I started playing 1.d4 in my slow games in the web. Opening theory was something I always disliked,

Question: what do you play after 1.d4 d5 ? If it's not 2.c4 or 3.c4 then 1.d4 e6 2.c4 doesn't make any sense.Also you should realize that fans of the Dutch will be very happy with 1.d4 e6 2.c4 f5.Alas 1.d4 e6 2.Nc3 d5 3.Nf3 Nf6 leaves White with 4.Bg5 Be7 5.Bxf6 Bxf6 6.e4 as best, which is a somewhat goofy variation of the Claasical French. And 3.Bf4 Bb4 might be not that enjoyable either.So those 45 lines are somewhat optimistic - after 1.d4 e6 White's best options are 2.e4. 2.c4 and 2.Nf3 indeed.Perhaps you shouls start with 1.b3 or 1.f4.

The book had the effect good books usually have: it made the stupids more stupid, the intelligent more intelligent and the other thousands of readers remained unchanged.GC Lichtenberg

Against after 1.d4 e6 2.Nc3 is recommended. It gives a disagreeable line for black if he wants to play the Dutch. 2... f5 3.e4 fxe4 4.Nxe4 Nf6 5.Bg5 gives white a small consistent space advantage.

But what to do in case of 2... d5 now. 3.e4 leads to the Winawer and that's a ton of lines. Is there any similar line for white after 2... d5 avoiding theory and keeping the small advantage in a position equal for IM up and disagreeable for black beyond that level?

I don't think 2.Nc3 makes sense unless you happy with d5 3.e4. If you play 2.e4 you can also avoid the Dutch and after 2.... d5 you can choose freely what you want to play against the French. So 2.e4 looks preferable to 2. Nc3 (unless of course you are happy with 3. Nc3 against the French in which case there is essentially no difference).

About two years ago I started playing 1.d4 in my slow games in the web. Opening theory was something I always disliked, mostly because I didn't understand how to work with it in a way having fun. For the first time now I found a repertoire being small enough to work with (45 lines for white against nearly everything from black) and seemingly solid enough to be expanded for some time. (https://www.chessable.com/course/102/).

Against after 1.d4 e6 2.Nc3 is recommended. It gives a disagreeable line for black if he wants to play the Dutch. 2... f5 3.e4 fxe4 4.Nxe4 Nf6 5.Bg5 gives white a small consistent space advantage.

But what to do in case of 2... d5 now. 3.e4 leads to the Winawer and that's a ton of lines. Is there any similar line for white after 2... d5 avoiding theory and keeping the small advantage in a position equal for IM up and disagreeable for black beyond that level?